The present invention relates to a method of fabricating a strip of electric contact springs for an electrical connector, said springs being united at their ends by two continuous side strips, the springs being displaced from the plane of said side strips by being twisted about their respective longitudinal axes that are perpendicular to the length of the strip.
Such a strip of electric contact springs is used in an electrical connector comprising two parts respectively connected to one or the other of members that are to be electrically interconnected, the strip being an intermediate contact member providing contact that is resilient, and being associated with one of the two parts. The connector can be plane and can have two contact plates between which the strip is placed, being associated with one of the plates, or it can be a coaxial cylindrical connector having a male portion and a female portion, one of these two portions including a housing for the strip.
The invention applies particularly, although not exclusively, to contacts for passing permanent currents in high voltage or medium voltage switchgear.
Document FR 2 339 259 describes, with reference to FIGS. 7, 10, and 11 of that document, a strip of electric contact springs of the type defined above. In that document, the strip of springs is made of a material that can be electrically conductive or non-conductive, and the central portions of the springs are coated in an electrically conducive material that envelops both of the edges of each spring. That disposition thus makes it possible to separate the two functions that are required to achieve contact that is both elastic and that provides good electrical conductivity. The material of the strip needs only be capable of ensuring that contact is elastic, as though it were a spring, and it no longer needs to have good qualities of electrical conductivity. However, the strip of springs described in the above document, in which each spring has a layer of electrically conductive material enveloping both edges of the spring, is not easy to fabricate, since each spring needs to be coated individually in its own conductive layer.
The present invention seeks to provide a method which ensures that a strip of electric contact springs is easy to fabricate.
The invention thus provides a method of fabricating a strip of electric contact springs for an electrical connector, said springs being united at their ends by two continuous side strips, the springs being displaced from the plane of said side strips by being twisted about their respective longitudinal axes that are perpendicular to the length of the strip, wherein the starting material is a strip of a plastically deformable material that is capable of acquiring elastic spring properties after treatment, at least the central portion of the strip is coated on only one of its two faces in a layer of a material that is a good conductor of electricity, said strip then being punched so as to obtain said springs and continuous side strips, and said springs are then displaced from the plane of said side strips by said twisting, and wherein one edge of each spring is folded down as a hem in the direction that ensures that the electrically conductive coating remains on the outside of the fold, and said strip is then subjected to hardening treatment to confer elastic spring properties thereto.
The invention also provides a strip of electric contact springs for an electrical connector, said springs being united at their ends by two continuous side strips, the springs being displaced from the plane of said strips by twisting about their respective longitudinal axes that are perpendicular to the length of the strip, said strip being made of a material having elastic spring properties, wherein at least the central portion of each spring is coated on one only of its faces in a material that is a good conductor of electricity, and wherein one of the edges of each spring is folded down as a hem in the direction which causes the electrically conductive coating to appear on the outside of the fold.